The Black Death pandemic hits harder in this alternate history and Europe never really recovered from it. Some other political conditions made it so that industrial revolution happened almost two centuries earlier.

Along with industrial revolution, came environmental destruction. At the end of 19th centuries, the clathrate gun hypothesis have been proven true and from there the rate of glacial melting rose exponentially. In only a century, sea level has risen ten meters. This catastrophe changed human society greatly, and the rate of technological advancement rose to an unprecedented level.

By 24th century, the sea level has stabilized at 30 meters higher than 19th century. Human's technological development had also plateaued once more.